Apparatus for the production of bulky yarns



Aug. 29, 1961 H. L. MARTYN 2,997,771

APPARATUS FOR THE PRODUCTION OF BULKY YARNS Filed Aug. 7, 1958 FlG.l

//7 van for Ham/0 L eW/s Many/7 By h/s of/omeys Z mm/M United States Patent 2,997,771 APPARATUS FOR THE PRODUCTION OF BULKY YARNS Harold Lewis Martyn, Allesley, Coventry, England, assignor to Courtaulds Limited, London, England, a British company Filed Aug. 7, 1958, Ser. No. 753,714 Claims priority, application Great Britain Aug. 30, 1957 5 Claims. (Cl. 28-1) This invention relates to apparatus for the production of bulky yarns.

A process has recently been developed, as described for example in United States patent specification No. 2,783,- 609 and British patent specification No. 762,630 for making bulky yarns by passing a bundle of continuous filaments through a turbulent zone produced, for example by a high velocity jet of air, to cause the filaments to form loops and convolutions at random intervals. Known constructions of air jets for carrying out this process have been found to give variable yarns even after standardization of the equipment, and jets which give satisfactory products when first used, tend to deteriorate with use and give inferior yarns.

The object of this invention is an improved construction of jet for making bulky yarns. The new jet is very effective, of simple construction and has a long useful life.

The jet of the present invention comprises a hollow body portion having an inlet for air under pressure, a yarn exit tube leading out of said body portion, a yarn entrance tube coaxial with the exit tube with its end extruding slightly into the exit tube leaving an annular passage for air between them, and the wall of the exit tube has in the vicinity of the end of the entrance tube a hole communicating with the interior of the hollow body portion. Preferably the air inlet is adapted to direct entering air towards the overlapping ends of the yarn entrance and exit tubes in a direction substantially at right angles to the common axis of said tubes.

The entrance and exit tubes are advantageously constructed of narrow tubing, that is to say with an internal diameter not exceeding 0.1 of an inch; the so-called hypodermic tubing is suitable for making both tubes. The internal diameter of the inlet tube should be sufficient to permit easy passage of the yarn to be treated.

Using such tubing, the overlap of the two tubes is preferably of the order of one tenth of an inch. In general the overlap may be of the order of one internal diameter of the exit tube. The diameter of the hole in the wall of the exit tube is conveniently about 0.02 to 0.05 of an inch.

The end of the exit tube where the filaments leave the jet is preferably flared to assist the bulking of the filaments.

Jets constructed in accordance with this invention are self-threading as the jet of air causes the filaments to be drawn into the entrance and exit tubes by suction.

The jet of the present invention may be employed in conjunction with means for feeding a yarn to the entrance tube of the jet at a controlled linear speed and means for withdrawing the yarn from the exit tube at a linear speed less than the inlet feed speed. Thus the yarn may be forwarded to the jet by feed rollers drawing the yarn overend from a stationary package and withdrawn from the jet and simultaneously wound by a constant speed winding device at a rate less than the feed rate, for example by to percent.

Yarns to be treated in the new jet preferably contain twist. For example, in the case of a yarn of 70 denier, the twist may be of the order of 12 turns per inch. If desired yarns treated in the jet may subsequently be twisted, for example in the course of collection by winding.

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The invention will now be more specifically described with reference to the accompanying drawings in which:

FIGURE 1 shows in enlarged cross section one form of jet in accordance with the invention;

FIGURE 2 shows an assembly of apparatus including the jet, means for supplying yarn to the jet, and means for collecting the treated yarn.

Referring to FIGURE 1, the jet comprises a hollow body portion 8 having a yarn entrance tube 1 and a coaxial exit tube 2, the tube 1 projecting slightly inside tube 2 to leave an annular space 3.

At right angles to the common axis of the tubes 1 and 2 and opposite the overlapping ends of the tubes is an air inlet passage 4 for introducing compressed air. The tube 2 has a hole 5 in its wall connecting the interior of the hollow body portion 8 with the interior of the tube 2. The end 6 of the block 7 surrounding partof the tube 2 is flared to assist in the bulking of the filaments.

Suitable dimensions for a jet as shown in the drawing are as follows:

Inch

Outside diameter of entrance tube 1 0.057 Inside diameter of entrance tube 1 0.044 Inside diameter of exit tube 2 0.073 Length of overlap of tubes 1 and 2 0.1 Diameter of hole 5 0.028

The jet may be used with air supplied at 45 cu. ft./ hr. at 30 lb./sq. inch.

Referring to FIGURE 2, the assembly of apparatus for processing a yarn comprises a jet, generally indicated at 9, of the kind shown in FIGURE 1. A set of feed rollers is provided including a driven roller 10 and freely rotatable rollers 11 and 12 resting thereon. A yarn 13 is drawn from a package 14 via guides 15 and 16 and forward it to the inlet tube 1 of the jet 9. The yarn is withdrawn from the jet 9 and wound into a package 17 which is surface driven by a roller 18, being traversed by the traverse guide 19. The rollers 10 and 18 are driven in synchronism by means not shown, the peripheral speed of the roller 18 being less than that of roller 10.

What I claim is:

1. A jet suitable for the production of a bulky yarn from a continuous filament yarn, said jet comprising a hollow body portion having an inlet for air under pressure, a yarn exit tube leading out of said body portion, a yarn entrance tube coaxial with the exit tube with its end extending slightly into the exit tube leaving an annular passage for air between them, and the wall of the exit tube having in the immediate vicinity of the end of the entrance tube a single radial hole communicating with the interior of the hollow body portion, the air inlet being adapted to direct entering air towards the overlapping ends of the yarn entrance and exit tubes in a direction substantially at right angles to the common axis of the said tubes.

2. A jet according to claim 1, wherein the exit end of the exit tube terminates in an outwardly flared portion.

3. A jet according to claim 1, wherein the internal diameter of the exit tube is less than 0.1 inch.

4. A jet according to claim 3, wherein the entrance tube extends intothe exit tube by about 0.1 inch.

5. Apparatus suitable for the production of a bulky yarn from a continuous filament yarn, said apparatus including a jet, said jet comprising a hollow body portion having an inlet for air under pressure, a yarn exit tube leading out of said body portion, a yarn entrance tube coaxial with the exit tube with its end extending slightly into the exit tube leaving an annular passage for air between them, the wall of the exit tube in the immediate vicinity of the end of the entrance tube having a single radial hole communicating with the interior of the hollow body portion, the air inlet being adapted to direct entering air towards the overlapping ends of the yarn entrance and exit tubes in a direction substantially at right angles to the common axis of the said tubes, means for feeding a yarn to the entrance tube of said jet at a controlled linear speed, and means for withdrawing the yarn from the exit speed.

References Cited in the file of this patent UNITED STATES PATENTS Breen Sept. 23, 1958 

1. A JET SUITABLE FOR THE PRODUCTION OF A BULKY YARN FROM A CONTINUOUS FILAMENT YARN, SAID JET COMPRISING A HOLLOW BODY PORTION HAVING AN INLET FOR AIR UNDER PRESSURE, A YARN EXIT TUBE LEADING OUT OF SAID BODY PORTION, A YARN ENTRANCE TUBE COAXIAL WITH THE EXIT TUBE WITH ITS END EXTENDING SLIGHTLY INTO THE EXIT TUBE LEAVING AN ANNULAR PASSAGE FOR AIR BETWEEN THEM, AND THE WALL OF THE EXIT TUBE HAVING IN THE IMMEDIATE VICINITY OF THE END OF THE ENTRANCE TUBE A SINGLE RADIAL HOLE COMMUNICATING WITH THE INTERIOR OF THE HOLLOW BODY PORTION, THE AIR INLET BEING ADAPTED TO DIRECT ENTERING AIR TOWARDS THE OVERLAPPING ENDS OF THE YARN ENTRANCE AND EXIT TUBES IN A DIRECTION SUBSTANTIALLY AT RIGHT ANGLES TO THE COMMON AXIS OF THE SAID TUBES. 